rmu09

So if you are a criminal that needs disposable SIM cards you just pay some cash-strapped person to get a bunch of prepaid ones for you.

That's a bleed resistor to discharge the capacitor when turning off, else it could keep dangerous charge for a long time.

ESR limits current inrush into the capacitor, with ceramic caps you would need some additional current limiting.

Voltage should not be that much of a problem, but there may be other issues with ceramic caps (like cracking due to thermal stress, voltage dependent capacity, microphoning, ...)

Could be the driver is designed for a specific range of equivalent series resistance of the capacitor. High ESR could help with peak current and EMC.

A smoke detector doesn't need that much power, so efficiency of the power supply is less of a concern. You have to find a useful compromise between efficiency and use of materials. Those additional components for higher efficiency need to be produced which uses resources and energy.

Although 15W standby for a garage opener seems excessive.

Asus Tinkerboard, Libre Computer LePotato. Both much more powerful than the RPi. Both available with eMMC which is much more robust than your typical sd-card.

A table saw should have a riving knife installed. AFAIK it is mandatory for CE.

I remember that even in 1997 you needed one boot-disk containing the kernel, somewhat taylored to your system (SCSI/non-SCSI, networking) already because of space constraints, and a root-disk, and the running system was pretty minimal.

Building more telescopes like LIGO, IceCube and a whole bunch of other "microphones" or "telescopes" or whatever you want to clal them.

But not sure if that qualifies as "experimental" particle physics.

I was really upset about the entanglement thing. It wasn't even necessary for the plot.

Charged particles radiate away energy if you accelerate them (force them on a curved path), this energy loss is larger for larger accelerations / smaller radii.

To bend the particle beam you need magnetic fields. Particles with more energy need larger fields. Larger radius means less field strength for given energy or larger energy for given field strength.

So a circular accelerator needs strong magnets nearly everywhere to force the beam on a circular path. In case you would put it in outer space, it's not like you just bounce the beam between some small number of spacecraft, that wouldn't gain much if at all, you would need something very similar to the structure in the LHC.

English is not my first language, so forgive me if I'm a bit ambiguous, it's not the intention.

CAM workstation (running some "generic" CAM package with machine specific configuration) in some office building was the precondition, in that case it will never make much sense to control a machine's servos from that workstation, in my opinion.

Integrating the CAM within the machine itself is something else, and yes, stuff like that existed for very long time, but that is something completely different IMHO.

The machine controller "knows" the physical limits because somebody configured it (and "locked" it). It would be hard to guarantee the integrity of this configuration if you put it on an arbitrary workstation to run CAM and machine control.

Low-level control your machine from your CAM workstation in the office building will never make much sense (where the CAM software directly talks to servos).

I would prefer my (probably expensive) machine to kind of "know" what it's physical limits are and guarantee that executed commands adhere to them.

I know of WFL millturns with crashguard.

AFAIK the crash guard is a separate component that relies on 3d models of the machine and the tools, it doesn't see anything.

If you workholding is weak and a piece comes loose the crash guard probably won't make a difference.

It should not be that hard to export current axis positions and get it into FreeCAD. Look at machinekit, they have remote control and toolpath display. Pause/run/start, override of feed and spindle speeds also is easy.

Detecting chatter is not that easy. Slowing down may be wrong, sometimes it is better to speed up.

Doing on-the-fly adjustments of toolpaths in CAM integrated into a machine control would be a major research project.

Real CNC machines have limit switches, they monitor the load on the axis and spindle servos etc etc. But that doesn't prevent running your cutter into a fixture at positioning speed and ruining the spindle bearings.

CAM can take a lot of time and need considerable computing resources. Not that much of issue today, but still, why do the same computations over and over again? Also, you will want to inspect the toolpaths before running them on real hardware.

It's not that easy. You need accurate models of your machine, the tools and the stock material. Your simulation has to be linked to the real machine movements and be ahead of time so you can estop the machine before the crash happens.

But that still doesn't help in case of insufficient workholding or breaking tools.

There are machines that are "self-aware" in the sense that they run a simulation parallel to the NC control, slightly advanded in time, to catch catastrophic crashes and ESTOP the machine. Cutting into the machine bed can be _very_ expensive.

Have a look at FreeCAD Path Workbench. You won't use it to run your 200000$ 5axis mill, the 3d kernel has limitations, and the UI isn't polished and has rough spots, but it is usable.

For controlling your machine there is LinuxCNC (formerly Enhanced Machine Controller, created at NIST) http://www.linuxcnc.org and the fork MachineKit http://www.machinekit.io/

Also, latest FreeCAD has a CAM module ("Path workbench") that has come a long way and really is useful.

GNU Health is a Free/Libre project for health practitioners, health institutions and governments. It provides the functionality of Electronic Medical Record (EMR), Hospital Management (HMIS) and Health Information System (HIS).

http://health.gnu.org

btrfs send will only work on btrfs filesystems, you probably also want to backup other stuff.

backuppc works really well, the drawback is that it is kind of slow if you have lots (millions) of files.

The 6502 in the 1541 runs at 1MHz, that is indeed a bit slower than the NTSC version C64 CPU (1.023MHz), but a bit faster than the PAL version CPU (0.985MHz)

Ice growth on a glacier is what remains of snow over one year. I don't know proper english jargon, but glaciers usually accumulate snow from around october to june. June to october is the melting period.

Obvious: glacier growing means it accumulates more snow (that will slowly convert into solid ice) than is melting in the summer.

For those who want to sync TiddlyWiki between multiple computers, there also is https://noteself.github.io/.

This TiddlyWiki-variant stores documents in the browser (pouchdb) and can sync to a couchdb-server.

Whatever non-ordinary matter would be, E=mc² should apply as well.

That number is an upper bound, I don't believe any process is known to convert matter into a useable form of energy with reasonable efficiency and yield. Neither fusion nor fission count as they only "convert"/release a tiny fraction.

The tool allows one to manipulate kernel objects more or less 1:1, so documentation and help of 'ip' and 'tc' is adequate enough if you know what those kernel objects are and how they behave, but it won't help if you don't know anything about linux networking or traffic shaping in the first place.

What's all the fuzz about this "sudden" change? iproute2 is part of linux (kernel) since 1999 or so.

I got 3 Samsung EVOs (from 2015 or so) that got stuck in a kind of "read only" mode after some months in the Pi. All seems normal for some time, but writes are not persisted. After some time linux gets confused and panics. After rebooting, FS is always in exact same state.